This disclosure relates generally to physical connections between an input/output (I/O) module and a terminal base in automation systems.
In general, I/O interfaces used in automation systems provide a method for transferring information between sensors, actuators, and automation components that include processors, external devices, internal memory, and external memory. Generally, the I/O module may perform various modifications of signals, while a terminal base supplies connections to peripheral devices, such as sensors and actuators, or processors. Peripheral devices may be electromechanical, electromagnetic, or simple electronic devices. I/O modules may act as a hub or receiving and distribution point for many different devices that provide signals used in automation processes, and signals that command operation of automation components in performing parts of such processes.
Furthermore, such modular I/O may be programmed to exchange signals or data derived from the signals with other automation components in specific ways. The use of a configured I/O module in a system leads to the requirement that only the correct I/O module be coupled to and implemented with the terminal base where it is to be used and the specific components connected via terminals in the base.
Keying systems on I/O interfaces allow only the I/O module with a proper key to fit into a terminal base that has been configured with a keying base to physically receive only that key. The I/O module with the proper key may be placed into the terminal base with no restriction, but an I/O module with a different key may be physically rejected from the base. The removal and engagement of I/O modules may be required due to replacement or upgrade. Additionally, if an upgrade is desired, it may be necessary to change the keying base to prevent the previous module from being placed in the terminal base. Unfortunately, keying bases are generally time consuming to configure and may be permanent once set.